Are Local, Near-Ground Emissions of Mercury and
Copper Significant Sources of Water Pollution?
Geoff Brosseau, BASMAA
Doug Steding/Christopher Conaway, UCSC – Mercury
Mark Schlautman, Clemson University – Copper
WRPPN Annual P2 Conference - 2003
Funding
 USEPA Great Waters Program (National
Estuary Program) – Air Deposition Initiative
Grant
 BASMAA (Bay Area Stormwater
Management Agencies Association)
 SFEP (San Francisco Estuary Project)
In the Beginning…
The Development and
Legacy of 70s Environmental
Protection Regulations
Lost in the Translation?
 Clean Water Act
 POCs / PBTs



Heavy metals
Pesticides
Toxics (OCs, PCBs,
PAHs, Dioxins/Furans)
 Sediment
 Clean Air Act
 HAPs / TACs



Ozone, VOCs
NOx, SOx
Nutrients
 PM (Particulate matter)
Lost in the Translation? (Cont’)
 Dimensions


ppm, ppb, ppt (ng/l)
Aquatic life-driven
 Discharges
 Point / Non-Point
 Watershed
 Dimensions


ppm (ng/m3)
Human health-driven
 Emissions/Deposition
 Stationary / Mobile /
Fugitive
 Airshed
Air Quality / Water Quality –
Previous National Work
 National studies concentrated on Chesapeake
Bay and Great Lakes
 Continental / Regional impacts
 First federally-funded air quality / water
quality studies west of the Mississippi began
in 1999
San Francisco Bay –
Previous AQ/WQ Work






Loading of Toxic Contaminants, AHI, 1987
Status and Trends, SFEP, 1991
Site-specific water quality objectives, San Jose, 1991
State of the Estuary, SFEP, 1992
Metals Control Measures Plan, SCVURPPP, 1997
Scoping Study of Air Deposition Monitoring
Information Relevant to Water Quality, BASMAA,
1998
BASMAA Scoping Study of
Air Deposition Monitoring Information
Relevant to Water Quality
 Prompted by increasing concern about air
pollution being a “source” of POCs
 Conducted preliminary review of both air
pollution monitoring and air quality / water
quality work
 Showed that air monitoring network was
unsuited for water quality POCs and source
control work
Air Quality / Water Quality
West Coast Studies
 Deposition


San Francisco Estuary Institute (SFEI)
Southern California Coastal Water Research
Project (SCCWRP)
 Emissions – BASMAA and SFEP – Develop
and implement a monitoring program for
specific emission sources to storm water in
San Francisco Bay Area watersheds
BASMAA / SFEP Study –
Scoping
 Candidate Pollutants of Concern
• Copper
• Dioxin
• PAHs
• Diazinon
• Mercury
• PCBs
 Selection criteria




Defined problem (303(d), WQO exceedances)
Storm water identified as significant pathway
Air emissions / deposition identified as significant pathway
Source identification/ characterization information needed
 Emissions – Near-ground


Mercury in tailpipe exhaust
Copper in brake pads
BASMAA / SFEP Study –
Scoping (Cont’)
 Mercury


Diesel exhaust was estimated source of 33% of mercury
to South San Francisco Bay and 80% of mercury in
urban runoff (SCVURPPP, 1997)
Sample and analyze fuels and lubricating oils
 Copper


Brake pads were estimated source of 42% of copper to
South San Francisco Bay and 80% of copper in urban
runoff (SCVURPPP, 1997)
Characterize physical and chemical properties of brake
pad wear debris
California Air
Resources Board
Mobile Laboratory
Sampling Plan
 39 total fuel samples


20 Diesel
19 Gasoline


13 Regular gasoline
6 Premium gasoline
 Semi-random locations



Refineries
Transfer stations
Service stations
Sampling Plan (cont’)
 25 samples – other automotive fluids



Motor oils
Lube oils
Gear oils
 Semi-random distribution of types and
weights
Analysis
 Fuels


Mercury – Cold Vapor Atomic Fluorescence
Spectrometry
Full suite of other metals – ICP/OES (direct
injection)
 Oils – Thermal decomposition method?
Results – Mercury in fuels
Fuel Type
Diesel
Regular
gasoline
Premium
gasoline
Concentration Standard
average (ppb) dev. (ppb)
0.142
0.064
No. of
Samples
20
0.542
0.444
13
0.474
0.331
6
Results – Other metals, Oils
 Other metals in fuels – Most of the metals
were below the detection limits with the
exception of Ni and Pb in a few samples and
Cu in one sample
 Oils – Mercury appears to be less than 10
ppb BUT analyses were problematic,
probably because of product formulation
Changing Load Estimates –
Mercury
 Diesel exhaust – 33% of load to South San
Francisco Bay (SCVURPPP, 1997)
 Atmospheric deposition – 7% of load to San
Francisco Bay (RWQCB, 2003)
 Gas / diesel fuel consumption (BASMAA /
SFEP, 2003 draft)


6% of atmospheric deposition
0.4% of load to San Francisco Bay
So, where’s the rest of the Hg
in air coming from?
 Regional – Bay Area plus surrounding Cos.





Medical waste incineration
Portland cement manufacturing
Municipal waste combustion
Carbon black production
Crude oil refining?
 International – Trans-Pacific fluxes from
Asia plus local smog
City of Palo Alto / BASMAA
Brake Pad Wear Debris Testing
 Sample – One copper containing brake pad
 Development of microwave digestion
techniques for brake wear debris
 Analyses




Determination of sample heterogeneity and
minimum sample size for representative results
Total copper concentration determinations for brake
wear debris
Specific surface area analysis
Copper solubility/leaching tests for model test
conditions and for environmentally-relevant
aqueous environments
Preliminary Results –
Copper in Brake Pads
 Wear debris particles are fine particulate
matter (~72% is 10 μm or smaller – PM10)
 Highly irregular shapes
 Upon initial release, about 47% of the
material was released into the air; about 49%
fell to the ground
SEMs of Brake Wear Debris
Source: Brake Manufacturers Council
Product Environmental Committee, 2001
Preliminary Results –
Copper in Brake Pads (cont’)
 Copper content depends on individual pad
 About 40% increase in copper use in pads between 1998 and
2000, with some probable increase between 1996 and 1998
 If results from one pad are typical, copper from vehicle
brake pads probably behaves in the environment like copper
from other environmental copper sources
 Copper solubility in brake wear debris is probably due to the
high surface area of brake pad wear debris and the chemical
form of the copper in the wear debris
Copper in Brake Pads –
Next Steps
Proposition 13 Grant – Brake Pad Partnership
 Chemical and physical characterization work
 Environmental transport and fate modeling




Source loading
Air deposition modeling
Watershed modeling
Receiving water modeling
 Environmental monitoring
Original Question
Are Local, Near-Ground Emissions of
Mercury and Copper Significant
Sources of Water Pollution?
 Mercury – No
 Copper – Yes, probably
Contact Info.
Geoff Brosseau
BASMAA
(Bay Area Stormwater
Management Agencies Association)
(510) 622-2326
gabrosseau@attbi.com